bug#61847: debug-early-backtrace only works some of the time.

[Alan Mackenzie]

Hello, Eli.

On Wed, Mar 01, 2023 at 19:04:32 +0200, Eli Zaretskii wrote:
> > Date: Wed, 1 Mar 2023 16:46:52 +0000
> > Cc: monnier@iro.umontreal.ca, 61847@debbugs.gnu.org
> > From: Alan Mackenzie <acm@muc.de>

> > > Some fancy Lisp facilities are already available anyway.  And I see no
> > > reason for this requirement in this case.

> > In a situation where Emacs does not bootstrap, instead crashing during
> > the loading or compiling of the Lisp files, we need a debugging tool
> > which isn't dependent upon those Lisp files.  That is what debug-early.el
> > is intended to be.

> You are saying that only Lisp code can crash and make debugging
> harder?  Have you never seen crashes inside prin1?

Of course not.  I'm saying that Lisp code, in early bootstrap, DOES
crash, and for that we need a suitable tool, namely debug-early.el.  For
other sorts of crashes we use other tools.  And no, I've never seen a
crash inside prin1.  That function was debugged long before I started
hacking on Emacs.

> Any code that prints arbitrary objects can crash.  That fact is not a
> useful argument for or against a particular alternative for such
> printing.

> Anyway, I don't see any point in continuing this argument.  It is
> clear that we disagree here, and the nature of the disagreement is
> also very clear.

Alright, but we still have a bug to fix.  I think (but I'm not sure)
that you agree that cl-prin1 in its current state isn't currently
adequate for debug-early.el.

You have rejected my proposed fix.  So what alternative do you propose?

-- 
Alan Mackenzie (Nuremberg, Germany).